Prior to introducing the trocar and cannula the usual procedure is to use an aspirating needle of about ⅛ inch bore and 3½ inch length. If the needle happens to be longer it should not be passed deeper than 3½ inches, in a person with a 32-inch chest, in order surely to avoid the vena cava. If there are no distinct localizing signs the needle should first be introduced in the eighth or ninth interspaces in the anterior axillary line and pushed backward, inward and slightly upward. Manson recommends at least 6 punctures before abandoning exploration. Cantlie does not think that a moderate degree of haemorrhage from the puncture of the liver will do harm in a case which is simply a liver congestion. One should always be ready to operate in case pus be found in the exploring needle. Leaving the needle in situ a small skin incision is made and a 4 or 5 inch by ⅜ inch trocar and cannula introduced along the line of the needle. Withdrawing the trocar some of the pus is allowed to escape through the cannula and there is then introduced a 6 × ½ inch piece of strong rubber drainage tubing, one end of which has lateral fenestrations but a closed tip in order that a long steel pin may put the tubing on the stretch so that it passes the smaller lumen of the cannula.
The cannula is then slipped out over the tubing and the external stretched end of the tubing released so that the contracting rubber fills the puncture. The steel pin used for introducing the rubber tube is then withdrawn and the tubing transfixed close to the skin with a safety pin.
After the cavity has drained of pus a dressing is applied. There are some who advocate aspiration alone without subsequent drainage. The dressing should be changed frequently and a connecting tube, draining into an antiseptic-containing bottle, should be attached to the tube in the cavity in order to obtain a syphoning action. Some aspirate and inject into the cavity about 2 ounces of 1 to 1000 emetine solution.
Some report favorably from the use of 1 to 1000 quinine irrigations. At present the hypodermic use of emetine will probably obviate the necessity of any irrigation.
There are those who think that a preliminary aspiration, followed by incision, after a few days of improvement in general condition, is the best method in serious cases.
It is usual to recommend a general anaesthetic when introducing the aspirating syringe or trocar and cannula. Local anaesthesia with quinine and urea hydrochloride, however, will usually suffice and lessen the dangers of shock in bad cases. Rib resections and even intra-abdominal procedures are best done under local anaesthesia provided the operator is familiar with the technic.
Newman has recently warned against the use of the small aspirator for diagnosis, pointing out that it is unreliable and that the diagnosis should be made by other diagnostic aids, including hypodermic use of emetine. He notes the occurrence of death from internal haemorrhage, the interference of the needle with the surgical incision and, further, the obscuration of the field of operation by pus where no adhesions exist and, finally, the danger of general peritoneal infection from a leak. He notes that the cavity may be under tension and that the pus may force itself along the track of the needle. He recommends incision and packing with gauze where adhesions do not exist and the exploration of the liver with dressing forceps instead of cutting into the liver with the knife.
Usual Operation for Liver Abscess
Either a vertical incision about the middle of the right rectus (Bevan) or a Kocher incision, parallel with the costal margin, may be used. The latter incision favors hernia if prolonged drainage is required. The hand is introduced into the abdominal cavity and the liver palpated. Often the borders of the site of a liver abscess give a hard feeling on palpation. If adhesions are not present the area should be packed off with gauze and the cavity opened by a dressing forceps, haemostat or thermo-cautery. It is often advisable to introduce a trocar and cannula and to drain off the excess of pus.